Jail cell lock mechanism

Abstract

A jail-cell door is suspended from an overhead carriage, for horizontal displacement between closed and open positions, and an elongate slide bar has a horizontal lost-motion connection to the carriage. The slide bar mounts a reversible electric motor and is continuously engaged to the driven one of two rollers from which the carriage and its cell door are suspended; the shaft for the other suspension roller is journaled in the carriage. For driving the cell door in the door-opening direction, the outer lost-motion limit determines an expanded wheelbase of door suspension, and for driving the cell door in the door-closing direction, the inner lost-motion limit determines a slightly reduced wheelbase of door suspension. The slide bar carries cam formations at or near its respective ends for determining locking-bolt action only at the fully closed and fully open positions of the door, and a deadlock device is pivotally carried at one end of the slide bar, serving the door-closed condition. Assurance against bodily harm upon door closing is inherent in the design of drive-roller engagement to the rail on which both rollers travel, the engagement being to provide drive-roller slip at a predetermined threshold of tractive force.

What is claimed is: 
     
       1. In a system for operating from a remote-control station one or more of a plurality of cell doors arranged substantially in horizontal alignment along a corridor or the like, wherein (a) a housing is located above each door and each door is roller suspended via its own carriage and rides a rail which extends horizontally in each housing, (b) a reversible electric motor drive is within each housing for selectively moving the associated door between open and closed positions, (c) a movable emergency release bar extends from the remote control station and through each housing, (d) a vertical locking head is adjacent each door and is connected to a bolt engageable with the associated door to hold the door in closed position, (e) a pivotal deadlock prevents vertical movement of said locking head while said bolt is holding the door in closed position, and (f) means carried by said release bar at each door is provided for operating said locking head for each door thereby unlocking all of said cell doors simultaneously; the improvement in which, at each cell-door location: (g) said deadlock means is pivotally mounted to a slide bar carried by said carriage and having limited horizontally guided lost-motion engagement to said carriage, said deadlock means at one limit of said lost-motion engagement having deadlock action to foreclose locking-head displacement from door-bolting position, and said deadlock means at the other limit of said lost-motion engagement having no deadlock relation with said locking head; (h) cam means on said slide bar coacts with said locking head for displacing the same out of door-bolting position, such coaction being in the course of slide-bar movement from said one to said other limit of said lost-motion engagement; and (i) said motor means is mounted to said slide bar and has an output shaft connected to drive at least one roller of said suspension; whereby, starting with a deadlocked bolted and closed condition of said door, and upon motor excitation in one direction, said one roller is driven to displace said slide bar from said one to said other limit of the lost-motion engagement, thereby unbolting said door so that, after reaching said other limit of the lost-motion engagement, continued motor drive in said one direction is operative to drive said carriage in any opening displacement of the door; and further whereby, starting with an open condition of said door, and upon motor excitation in the opposite direction, said roller may be first driven to displace said slide bar from said other to said one limit of the lost-motion engagement and continued motor drive in said opposite direction is operative to drive said carriage in a closing displacement of the door, with said cam means returning the locking head to door-bolting and dead-locked condition upon completion of the door-closing displacement. 
     
     
       2. The improved system of claim 1, in which said deadlock means is spring urged to a normal pivoted position of deadlocking relation to said locking head, and in which actuation of said emergency release bar is operative to pivot said deadlock means against spring action and out of deadlocking relation with said locking head. 
     
     
       3. The improved system of claim 1, in which said roller is one of two longitudinally spaced rollers for each carriage, the second of said rollers being pivotally connected to said carriage and therefore not subject to the lost-motion displaceability of said one roller. 
     
     
       4. The improved system of claim 1, in which the horizontal guidance of the lost-motion engagement is via one or more longitudinally spaced rolls riding one or more horizontal ways. 
     
     
       5. The improved system of claim 4, in which the number of spaced rolls is two. 
     
     
       6. The improved system of claim 5, in which said two spaced rolls are connected to said slide bar at equal but longitudinally opposed distances from motordrive connection to said one roller. 
     
     
       7. The improved system of claim 1, in which said slide bar extends substantially the length of said carriage, said cam means being a first of two cams, of opposing slope at or near the respective ends of said slide bar, whereby upon approach to and attaining the door-open limit of carriage displacement, said locking head may be operative to bolt the door in its open position. 
     
     
       8. The improved system of claim 1, in which the engaged area of said one roller riding said rail is so selected in terms of the gravitational load upon the engaged area and in terms of motor torque deliverable to said roller, that a safety threshold of tractive force characterizes the roller-to-rail engagement, said safety threshold being selected to preclude bodily harm to an individual caught in the path of door-closing displacement.